Question
In the circuit shown, lamp P is rated 250V, 50W and lamp Q is rated 250V, 200W. The two lamps are connected in series to a 250V power supply.
Assume that the resistance of each lamp remains constant.
Which statement most accurately describes what happens when the switch is closed?
A Lamp P emits four times as much power as lamp Q.
B Lamp P emits twice as much power as lamp Q.
C Lamp Q emits four times as much power as lamp P.
D Lamp Q emits twice as much power as lamp P.
Answer/Explanation
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Question
A circuit contains two resistors, P and Q, and a power supply of negligible internal resistance, as shown.
The current in resistor P is 2.0A and the power dissipated by resistor P is 18 W. Resistor Q dissipates 240 J of energy when a charge of 40 C passes through it. What is the electromotive force (e.m.f.) of the power supply?
A 3.0V B 6.0V C 9.0V D 15V
Answer/Explanation
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Question
A cell of electromotive force (e.m.f.) E and internal resistance r is connected to a resistor of
resistance R.
A maximum power P can be dissipated by the resistor without overheating.
Answer/Explanation
Question
The diagram shows a thundercloud whose base is 500 m above the ground.
The potential difference between the base of the cloud and the ground is 200 MV. A raindrop with
a charge of 4.0 × 10–12C is in the region between the cloud and the ground.
What is the electrical force on the raindrop?
A 1.6 × 10–6N B 8.0 × 10–4N C 1.6 × 10–3N D 0.40N
Answer/Explanation
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Question
A cell of negligible internal resistance is connected to resistors R1, R2 and R3, as shown. The cell
provides power to the circuit and power is dissipated in the resistors.
Which word equation must be correct?
A power dissipated in R1 = power dissipated in R2 + power dissipated in R3
B power dissipated in R2 = power dissipated in R3
C power output of cell = power dissipated in R1 + power dissipated in R2 + power dissipated in R3
D power output of cell = power dissipated in R1
Answer/Explanation
Ans